Patent document 1 discloses a scheme that electronic tags, each of which retains tag information such as a commercial article ID (Identification) and a unit price, are attached to commercial articles, while a client provided with a cart for carrying the commercial articles obtains the tag information from the electronic tag attached to commercial articles on the cart to register the tag information in a table, further obtains selling prices of the commercial articles from a server and totalizes the selling prices, and thereafter the information is displayed based on contents of the table on the screen.
Further, Patent document 2 discloses a scheme that an RF (Radio Frequency) tag, which retains commercial article information including prices, functions and a quantity of commercial articles and related commercial articles information, is attached to a commercial article or a label of the commercial article and a tag reader held in a shopping cart obtains the commercial article information from the RF tag, a total amount calculating unit calculates a total amount, and an information display unit displays the total amount and the commercial article information.
Thus, a conventional shopping basket device attached to the cart obtains information such as a price of commercial article and a function of the commercial article from the electronic tag to register the information in the table. The shopping basket device executes a lot of processes such as counting identical commercial articles, calculating a total amount, generating specification information, and generating screen data for screen display.
If the shopping basket device is configured to execute the lot of processes, however, a processing capability corresponding to the lot of processes is required of the shopping basket device. Hence, a size and a weight of the shopping basket device increase. Therefore, it leads to a problem that the shopping basket device resultantly reduces the capacity of the shopping basket of the cart. Moreover, if the shopping basket is of a portable type fitted with a handle, such a problem arises that the shopping basket is not carried offhand due to the weight of the shopping basket device.    “Patent document 1” Japanese Patent Laid-Open Publication No. 2000-259947 (Paragraphs 0025-0027)    “Patent document 2” Japanese Patent Laid-Open Publication No. 2004-106827 (Paragraphs 0034-0037) “Disclosure of the Invention”